This invention relates to the field of chucks for rotating cores. Hollow cores formed of paper or metal are used for winding paper and the like into rolls and similarly for unwinding supplies of such materials. Core chucks are inserted into the core and then expanded to engage the inside diameter of the core. The chucks are attached to rotating shafts which thereby permit rotation of the cores for the desired purpose.
Core chucks are not new in the art and, for example, see the patents described in the prior art section of this specification. Generally, core chucks are of two types: pneumatically expandable and tapering. The pneumatic type expands the core engaging element by use of air or hydraulic pressure. The tapering type usually employ a shoe or tapered element which is cammed into engagement with the core.
While these prior chucks are generally satisfactory, it is desirable to simplify the construction while at the same time insuring an even, firm grip on the core to prevent slipping and/or damage to the core by uneven pressure. An approach ideally suited to meet these criteria is the use of a lathe chuck mechanism in conjunction with expandable jaw sections. Such a construction would insure that the jaw sections are evenly tensioned as they expand into the core and that a tight, firm grip will be maintained on the core. Further, such a construction is relatively low in cost and simple in design rendering maintenance significantly less than with prior designs.
It is accordingly an object of the present invention to provide an improved core chuck which is highly reliable yet simple and low cost in design.
Another object of the invention is to provide a core chuck which employs a lathe chuck adjusting mechanism in conjunction with core gripping sections to accurately, firmly and evenly grip a core.
A further object of the invention is to provide a low cost core chuck suitable for use in shaftless operations wherein the drive shaft need not pass through the chuck.
Other objects and advantages of the invention will be apparent from the remaining portion of the specification.